明善恶，辨是非是做人的基本品质。青少年要在复杂的社会生活中做出正确选择，应做到（   ）
①学会理性分析   ②树立美好理想     ③树立正确的良知标尺   ④选择好榜样   

    Today is Saturday. In the morning, Xiaoyong is sleeping, but the phone rings. He wakes up from his dream. He gets up and goes to the park near his home. He is doing exercise, but it starts to rain. He has to go home. He is doing his homework at home, but the bell rings.

    In the afternoon, Xiaoyong is riding his bike, but suddenly(突然)a little dog runs to him. He falls off his bike. He is so sad.

我国历史上的第一个王朝是禹建立的____。